Some systems provide the ability to modify read-only data while preserving an original copy of the data. For example, if a backup application is running, then the data being backed up must often be “frozen” (e.g., by making it read-only) in order to properly perform the backup. However, if modification of the read-only data (without touching an original copy of the data) is permitted, then other applications can run simultaneously while the backup application is running. Performance improvements in such systems would be desirable, for example so that the application which is running at the same time as the backup application is able to run faster. Oftentimes, there is a user interacting with the application and it is undesirable to keep a user waiting.